Image display systems create images by emitting, or modulating, light. The light forms an array of picture elements, or pixels, which together form a viewable image. Full-color images are created by either simultaneously or serially creating three independent single-color images. Cathode ray tube (CRT) based display systems use three electron guns to simultaneously stimulate three color generating regions for each pixel on the CRT screen. These three colors must be selected carefully in order to ensure that combinations of the colors are able to accurately recreate the full-color image source.
Intensity, or image brightness, is only one of many metrics, including horizontal and vertical resolution, color purity, display size, frame rate, and immunity from device created image artifacts, by which display systems are judged. Some of these characteristics are more important to consumers, either because they create a noticeably superior image, or simply because they differentiate between the systems on display in a store. Brightness is one metric that is extremely important to purchasers of display systems. Therefore, system designers must attempt to increase brightness in order to satisfy consumers and increase sales.
One factor that contributes directly to image brightness, is the available brightness of the light sources used to generate an image. Some systems may use colored light sources, others will use white light sources that are filtered to obtain the desired component colors. Filtering light necessarily reduces the useable brightness of the light source. The efficiency of the filters is a function of the wavelengths selected by the filter. Furthermore, the wavelengths selected by the filter impact the purity of the image produced by the display system. Therefore, an improved filter selection process will improve both the image brightness and color purity of a display system